Time dependent self-expiring visitor labels and badges are well known and presently manufactured and sold by TEMTEC Division of Brady Worldwide, Inc., see for example U.S. Pat. No. 4,903,254. Generally, these labels comprise two parts: a) a front part wherein the rear surface is coated with a pressure sensitive adhesive and the front surface is white, and b) a back part having migrating ink printed on one surface thereof. Printed on the white front face of the front part are the security design and other data, such as the visitor's name, date, time of entry, etc. When the pressure sensitive adhesive on the front part is contacted with the migrating ink printed on the back, the label or badge is activated. After a predetermined period of time the dye bleeds through to the white front part.
This VCP (visually changing paper) technology produces images and colors that appear after a predetermined period of time after activation. The process is primarily physical and chemical in nature and does not employ reactive chemistry, although it may. In known methods and devices, in order to initiate the timing function, a physical assembly must take place that puts the migrating dye materials (on the Back Part) in contact with an active dye absorber layer (the Front Part). Typically this is accomplished with a pressure sensitive adhesive Front Part label applied to the Back Part that is printed with migrating ink The adhesive of the Front Part label contacts the migrating ink dye and initiates the dye diffusion process.
The variable data, e.g., name of the visitor or attendee is usually added to the front part prior to or after activation. When the variable data is written by hand with a pen or marker, it can be done prior to or after activation. However, when a printer is used to add the variable data it is generally always performed before the label is activated because after activation the label is too thick and/or has misaligned substrates making the label difficult or impossible to pass through a printer.
Typically the printer used for applying the variable information to the front part of the label is a dot matrix printer, direct thermal printer, or thermal transfer printer. Once the front part of the label has been printed with the variable data it is removed from the printer and adhesively attached to the surface of the back part that has the migrating ink printed thereon. This activates the self-expiration process of the time dependent label. Typically within a day, the white surface or a portion of the white surface on the front of the label turns red to show its expiration.
There are numerous patents issued that cover the aforedescribed type self-expiring badges, labels and passes. Examples of these products and the technology used by these products are described in the following Haas patents and application, e.g., U.S. Pat. Nos. 5,364,132; 5,446,705; 5,602,804; 5,699,326; 5,715,215; 5,719,828; 5,785,354; 5,822,280; 5,873,606; 5,930,206; 5,957,458; 6,295,252; 6,452,873; and 2002/0105183. The entire disclosures of all of these patents and application are incorporated herein by reference. The products described in these patents have become widely accepted as a means for controlling and improving visitor security and as temporary badges. However, all of these products contemplate the use of a printer prior to activation followed by manual activation, i.e., the front part is manually placed on the back part to activate the time process.
This manual assembly and activation after the printing process in order to issue the self-expiring badges or labels creates certain difficulties. Some of these difficulties are: misalignment of the front part when it is attached to the back part, the length of time required to peel the release liner from the front part and attaching the front part to the back part, the litter caused by the release liners, and the most serious problem, the issuer of the badge failing, by accident or intent, to assemble the two parts. Without proper assembly, the visitor receives a badge with a front part that is continuously valid because it has not been activated to expire.
Other U.S. Patents of interest or relevance are the following:
U.S. Pat. No. 6,524,000 to Roth describes time-temperature indicators activated with direct thermal printing.
U.S. Pat. No. 6,384,854 to lbs et al. discloses a printer controller, e.g., a microprocessor, which is used to control the printing process. Substrates can comprise an identification card blank for receiving thermal printing. The ribbon can comprise a thermal resin.
U.S. Pat. No. 2002/0191066 to Bouchard et al.
U.S. Pat. No. 6,433,807 to Francis et al.
U.S. Pat. No. 5,956,067 to Isono et al.
U.S. Pat. No. 5,633,836 to Langer et al.
U.S. Pat. No. 4,916,112 to Henzel et al.